Aluminide compounds of selected ternary ruthenium and iridium systems

Studies of the Al-Ni-Ru and Al-Ir-Ru systems reveal their solidification st ructures and phase compositions. Both systems have a continuous isostructur al B2 phase field between AlRu and the aluminide of the other component. So me phases also showed extensions into the ternary: Al13Ru4 to similar to 10 at. % Ni or 12 at. % Ir; Al13Ir4 to similar to 11 at. % Ru, and Al2.7Ir to similar to 10 at. % Ru. The remaining binary phases have limited extension into the ternary. Also, each system has an Al-rich ternary phase: similar to Al14Ni2Ru and similar to Al52Ir20Ru27, respectively. Hardness tests unde rtaken across the systems were used to characterize the mechanical properti es and likely applications of some of the alloy compositions. The results a re plotted on solidification projections and compared. The uses of these ph ase diagrams as indicators for potential strengthening mechanisms is also d iscussed.